Head Gasket for 998T
Turbo Mini Forums

So I have the same composite (modern) head gasket.
Went to the track with my 998 Turbo last Saturday. Did 100km with 0.8bar (12psi) of boost, RPM between 3500 and 6500. Worked as a charm, absolutely no problems, just drive and let it cool down every 20 minutes. So this gasket seems OK to me, so far.

Edit: the air temperature after I/C was about 55C full throttle.

Edited by alpa on 29th Oct, 2010.

std 998 A+, g295, MD266, RHF4, 109hp @0.8bar/5400rpm

where is the thread about your trackday ?

Rusty by nature

std 998 A+, g295, MD266, RHF4, 109hp @0.8bar/5400rpm

On 10th Sep, 2010 wil_h said:
I thought that I should update this thread with my experience of the 'new kid in town gasket'

Basically I have now had two failures of the new gasket, one after a few thousand miles, one after a few hundred, so the first failure:

After lunching a copper gasket when I had boost control issues and lots of det I put one of the black ones on, this was just before Le Mans. I was running around 8psi, no pinking, no overheating, a nice relatively unstressd life for a head gasket. It then failed catastrophically. You can see the photo below.



Now, it has to be mentioned that I had torqued the head to 68Nm (as standard) but the gasket packet specified staged torquing 20Nm, 40Nm then 54Nm.

The following photo shows another firering with damage and likely to fail soon:



I therefore put this failure down to me over-torquing the gasket.

So, on to the second failure. This time I torqued to 54Nm in stages as specified. The gasket failed, with a leak from cylinder to coolant, see photo:



Now, having experience of this type of failure I know it's owing to under-torquing. I calibrated my wrench last month by the way, but it's unlikey to be high at 68Nm and low at 54Nm in any case.

I'm not suggesting that this gasket is a pile of junk, just it may not be suitable for the extra heat and pressure of a turbo engine.

My advice is that the Copper type (that are half the price) are more than up to the job and I wouldn't suggest using the Black type.

I'd be interested in others experience. It is worth noting that these gaskets are not in any way the same as the BK450 in material or construction and that the fire rings on the copper gaskets are actually thicker.

I hope this is of use to some.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

Well I have had other head gasket failures with the copper ones. But they have all be det related owing to one thing or another.

These failures were definately clamping faults, too low and too high.

At £20 a pop I'm not going to get any more.

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

www.twin-turbo.co.uk

Thanks, I'll stick with copper for the new engine then.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

any suggestions for using a 1275 head on the 998? I remember MRA doing a headgasket a while back and something mentioned on minispares.

Use the BK450 for that set up. Is is only the 998 on 998 gasket that is problematic.

http://www.twin-turbo.co.uk
http://www.hillclimbandsprint.co.uk/default.asp

A man without a project is like a like a woman without a shopping list.

Someone posted earlier that one can NOT use a 1275 head gasket with a small bore head and small bore block-- hogwash. I've done it and the car is still running the same gasket to this day. Someone had pocketed the block for a 1275 head. The pockets were into the fire ring on a small bore gasket but ok on the large bore gasket. You DO need to pay attention to one coolant passage, but you can either nick/file the gasket a bit or chamfer the hole in the block or both. But it WILL work in a NA car (it is not turboed so can't speak to that, but I don't see any difference).

Changing topics now:

While tuning our bodged-on metro turbo setup at the track with our 998 block and 12G1316 head, and subsequently trying to race it for 16 hours that weekend, we went through 2 copper gaskets because of detonation issues. By Sunday with pulled timing we were running ok but only recently did I pull off the head to replace it because it was known to be cracked. For the last head gasket change we used the TAM -whatever black gasket. The water passages are NOT as accommodating to our 998 block/1275 head combination-- they don't have enough wiggle room to make the water jackets line up as nicely. The Copper AF460 (?) gaskets work nicely. What like up even better are the super-cheap aluminized budget gaskets, but I wouldn't want to run those on a turbo.

Just my experience: Your mileage may vary.

That seems odd to me. On all the 998 heads I have, the fire ring on the 1275 gasket overlaps a water hole, so all you do is fill two cylinders up with water.

I guess with BL tolerances, sometimes you get away with it and sometimes you don't. I would advise anyone trying it to offer the gasket up to the head and checking around the fire rings before fitting.

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

www.twin-turbo.co.uk

Still using my car with this composite gasket, no known problems. I must have done at least 10000km since I installed it. Including engine mapping, 1/2 track day and regular full boost accelerations.

std 998 A+, g295, MD266, RHF4, 109hp @0.8bar/5400rpm

Anyone else got any long term experience of these black composite 998 head gaskets?

I'm about to bolt the head on the new build, but I've only got a black one to hand.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

I have one of these on my car now. It seems ok so far but it's only done about 300 miles.

The details in the gasket did quote a lower nm figure than the book... I can't remember which one I went for in the end.

The coppers did seem to seep a bit of water this one hasn't so far.

It's getting a thrash on the rollers tomorrow so we will se how it holds but then I have limited boost...

I run a supercharger and I don't care the TB is on the wrong side.
VEMS + 12 PSI + Liquid Intercooler = Small Bore FUN!

would that be the crewes missiles day? if so i'll see you there.

one day boost will be mine!